The strollers I always see at the MK are big and clunky and appear to be very uncomfortable for the rider. Unless you put some sort of padding (like a blanket) down, the strollers I have seen are the hard plastic and can get hot easily.
none of my 3 kids complained about any discomfort and we also broght along a LIGHT colored towel to lay over the front (to help block the sun). Our DD6 slept MANY times in the double and was very grateful to be riding and not walking. She used our backpack as a pillow! Best $15/day purchase we ever made.
Yes! You can get whatever size you want and there IS a lot more room in the double. Your child will thank you later! It is $8/day for single, $15/day for double. You can use your stroller pass to go park hop with you per day. Don't forget to get your Disney dollar for returning your stroller! When you get to the park in the morning, look for the CM outside the gate (at MK anyway, inside at AK) who is at a podium who you pay and get your stroller pass from. Then you go directly to the stroller pickup instead of waiting in the mousetrap, I mean line. Also, you can pre-purchase for "x" amount of days, but there was no discount for doing this, but it does mean you don;t have to worry about making that payemtn each day. Bring a lght colored, cheap towel to drape over the front if it gets really hot and sunny and a cheap COLORFUL bandana, etc. to tie around the handle. You will find your stroller much easier after the CM's move them while you are enjoying a ride.